APPARATUS AND METHODS FOR SPLIT-FEED COUPLED-RING RESONATOR-PAIR ELLIPTIC-FUNCTION FILTERS

摘要

A filter has coupled pairs of resonators positioned between and planar to split feed lines. The filters are further positioned orthogonal to the signal path. The filter has two pairs of resonators. Coupling extensions of the split feed lines are substantially parallel to each other. The resonators couple with the split feed lines at the coupling extensions. The resonators in each pair also couple to each other. The topology effectively forms an Elliptic Function response bandpass filter with high close-in frequency rejection capability. The filter can be cascaded to provide improved frequency rejection. Further, this topology may be relatively inexpensively produced using standard lithography techniques.